trw forged pistons

[mopar367]

i got a set of reconditioned ly rods with arp bolts to use for my .030 over 440 engine build. the rods came with trw forged popup pistons. my question is my 440 block is machined .030 over and fitted with cast silvolite pistons. it is my understanding that forged pistons require a bit more clearance in the bore. i measured both pistons. the trw forged is .002 smaller on the skirt than the cast silvolite. is this to account for piston expansion? if my piston has .004 clearance to the bore would this be ok for a forged piston?

 

[Meep-Meep]

The clearance is in the piston not the bore. Yes, the typical forged piston alloy grows a bit more than an alloy with a higher silicon content so more room is required. .004" - .005" is about right for the TRW's.

 

[67 B-body]

The manufacture will specify the piston to wall clearance for their product. Some are egg shaped and end up round after heat expansion to help with this.
GOOGLE is your friend....

 

[mopar367]

thanks guys thats mainly what i was wondering. so the clearance is in the piston not the bore. makes sense. i measured and there was .002 thou difference

 

[racedodge]

The manufacture will specify the piston to wall clearance for their product. Some are egg shaped and end up round after heat expansion to help with this.
GOOGLE is your friend....

if google had all the answers, then we wouldnt have this forum would we? He doesnt need google, he has you all! :headbang: